The transition from Vue 3 to Vue 4 is absolutely worth it (especially now with the reduced price of the download version)! Volumetric atmospheres, direct poser support, much improved render quality and just overall a lot better functionality and support for various model formats and texturing (I know I'm leaving stuff out but those are the major things I can think of at the moment). You will notice an amazing difference (at least I did) between the renders from Vue 3 and from Vue 4. I unfortunately can't say much on the animation side as I am just now starting to get more into the animation side of things with Vue 4 Pro, but you only really need mover to translate poser animations, I find the animation tools to be just fine without it. I'd have to agree with wabe too, download the demo and see what there is for you. Personally I've never looked back, which is something I can't say yet on the transition from Vue 4 to Vue 5.